Combinations of anti-cancer pharmaceutical therapeutics administered simultaneously or sequentially in a dosing regimen are now common in cancer treatment. Successful combination therapy provides improved and even synergistic effect over mono-therapy, i.e. pharmaceutical treatment limited to one drug (Ouchi et al (2006) Cancer Chemother. Pharmacol. 57:693-702; Higgins et al (2004) Anti-Cancer Drugs 15:503-512). Preclinical research has been the basis for prediction of clinical stage synergy of anti-cancer pharmaceutical therapeutic combinations such as capecitabine and taxanes for the treatment of breast cancer (Sawada et al (1998) Clin. Cancer Res. 4:1013-1019). Certain doses and schedules of combination therapy can improve safety without compromising efficacy (O'Shaughnessy et al (2006) Clin. Breast Cancer April 7(1):42-50). Synergistic effects in vitro have been correlated with clinical stage synergy (Steinbach et al (2003) Clin. Inf. Dis. October 1:37 Suppl 3:S188-224).
Upregulation of the phosphoinositide-3 kinase (PI3K)/Akt signaling pathway is a common feature in most cancers (Yuan and Cantley (2008) Oncogene 27:5497-510). Genetic deviations in the pathway have been detected in many human cancers (Osaka et al (2004) Apoptosis 9:667-76) and act primarily to stimulate cell proliferation, migration and survival. Activation of the pathway occurs following activating point mutations or amplifications of the PIK3CA gene encoding the p110a PI3K isoforms (Hennessy et al (2005) Nat. Rev. Drug Discov. 4:988-1004). Genetic deletion or loss of function mutations within the tumor suppressor PTEN, a phosphatase with opposing function to PI3K, also increases PI3K pathway signaling (Zhang and Yu (2010) Clin. Cancer Res. 16:4325-30. These aberrations lead to increased downstream signaling through kinases such as Akt and mTOR and increased activity of the PI3K pathway has been proposed as a hallmark of resistance to cancer treatment (Opel et al (2007) Cancer Res. 67:735-45; Razis et al (2011) Breast Cancer Res. Treat. 128:447-56).
Phosphatidylinositol 3-Kinase (PI3K) is a major signaling node for key survival and growth signals for lymphomas and is opposed by the activity of the phosphatase PTEN. The PI3K pathway is dysregulated in aggressive forms of lymphoma (Abubaker (2007) Leukemia 21:2368-2370). Eight percent of DLBCL (diffuse large B-cell lymphoma) cancers have PI3CA (phosphatidylinositol-3 kinase catalytic subunit alpha) missense mutations and 37% are PTEN negative by immunohistochemistry test.
Phosphatidylinositol is one of a number of phospholipids found in cell membranes, and which participate in intracellular signal transduction. Cell signaling via 3′-phosphorylated phosphoinositides has been implicated in a variety of cellular processes, e.g., malignant transformation, growth factor signaling, inflammation, and immunity (Rameh et al (1999) J. Biol Chem. 274:8347-8350). The enzyme responsible for generating these phosphorylated signaling products, phosphatidylinositol 3-kinase (also referred to as PI 3-kinase or PI3K), was originally identified as an activity associated with viral oncoproteins and growth factor receptor tyrosine kinases that phosphorylate phosphatidylinositol (PI) and its phosphorylated derivatives at the 3′-hydroxyl of the inositol ring (Panayotou et al (1992) Trends Cell Biol 2:358-60). Phosphoinositide 3-kinases (PI3K) are lipid kinases that phosphorylate lipids at the 3-hydroxyl residue of an inositol ring (Whitman et al (1988) Nature, 332:664). The 3-phosphorylated phospholipids (PIP3s) generated by PI3-kinases act as second messengers recruiting kinases with lipid binding domains (including plekstrin homology (PH) regions), such as Akt and PDK1, phosphoinositide-dependent kinase-1 (Vivanco et al (2002) Nature Rev. Cancer 2:489; Phillips et al (1998) Cancer 83:41).
The PI3 kinase family comprises at least 15 different enzymes sub-classified by structural homology and are divided into 3 classes based on sequence homology and the product formed by enzyme catalysis. The class I PI3 kinases are composed of 2 subunits: a 110 kd catalytic subunit and an 85 kd regulatory subunit. The regulatory subunits contain SH2 domains and bind to tyrosine residues phosphorylated by growth factor receptors with a tyrosine kinase activity or oncogene products, thereby inducing the PI3K activity of the p110 catalytic subunit which phosphorylates its lipid substrate. Class I PI3 kinases are involved in important signal transduction events downstream of cytokines, integrins, growth factors and immunoreceptors, which suggests that control of this pathway may lead to important therapeutic effects such as modulating cell proliferation and carcinogenesis. Class I PI3Ks can phosphorylate phosphatidylinositol (PI), phosphatidylinositol-4-phosphate, and phosphatidylinositol-4,5-biphosphate (PIP2) to produce phosphatidylinositol-3-phosphate (PIP), phosphatidylinositol-3,4-biphosphate, and phosphatidylinositol-3,4,5-triphosphate, respectively. Class II PI3Ks phosphorylate PI and phosphatidylinositol-4-phosphate. Class III PI3Ks can only phosphorylate PI. A key PI3-kinase isoform in cancer is the Class I PI3-kinase, p110α as indicated by recurrent oncogenic mutations in p110α (Samuels et al (2004) Science 304:554; U.S. Pat. No. 5,824,492; U.S. Pat. No. 5,846,824; U.S. Pat. No. 6,274,327). Other isoforms may be important in cancer and are also implicated in cardiovascular and immune-inflammatory disease (Workman P (2004) Biochem Soc Trans 32:393-396; Patel et al (2004) Proc. Am. Assoc. of Cancer Res. (Abstract LB-247) 95th Annual Meeting, March 27-31, Orlando, Fla., USA; Ahmadi K and Waterfield M D (2004) “Phosphoinositide 3-Kinase: Function and Mechanisms” Encyclopedia of Biological Chemistry (Lennarz W J, Lane M D eds) Elsevier/Academic Press), Oncogenic mutations of p10 alpha have been found at a significant frequency in colon, breast, brain, liver, ovarian, gastric, lung, and head and neck solid tumors. About 35-40% of hormone receptor positive (HR+) breast cancer tumors harbor a PIK3CA mutation. PTEN abnormalities are found in glioblastoma, melanoma, prostate, endometrial, ovarian, breast, lung, head and neck, hepatocellular, and thyroid cancers.
PI3 kinase is a heterodimer consisting of p85 and p110 subunits (Otsu et al (1991) Cell 65:91-104; Hiles et al (1992) Cell 70:419-29). Four distinct Class I PI3Ks have been identified, designated PI3K α (alpha), β (beta), δ (delta), and ω (gamma), each consisting of a distinct 110 kDa catalytic subunit and a regulatory subunit. Three of the catalytic subunits, i.e., p110 alpha, p110 beta and p110 delta, each interact with the same regulatory subunit, p85; whereas p110 gamma interacts with a distinct regulatory subunit, p101. The patterns of expression of each of these PI3Ks in human cells and tissues are distinct. In each of the PI3K alpha, beta, and delta subtypes, the p85 subunit acts to localize PI3 kinase to the plasma membrane by the interaction of its SH2 domain with phosphorylated tyrosine residues (present in an appropriate sequence context) in target proteins (Rameh et al (1995) Cell, 83:821-30; Volinia et al (1992) Oncogene, 7:789-93).
Measuring expression levels of biomarkers (e.g., secreted proteins in plasma) can be an effective means to identify patients and patient populations that will respond to specific therapies including, e.g., treatment with chemotherapeutic agents. There is a need for more effective means for determining which patients with hyperproliferative disorders such as cancer will respond to which treatment with chemotherapeutic agents, and for incorporating such determinations into more effective treatment regimens for patients, whether the chemotherapeutic agents are used as single agents or combined with other agents.
The PI3 kinase/Akt/PTEN pathway is an attractive target for cancer drug development since such agents would be expected to inhibit cellular proliferation, to repress signals from stromal cells that provide for survival and chemoresistance of cancer cells, to reverse the repression of apoptosis and surmount intrinsic resistance of cancer cells to cytotoxic agents. PI3 kinase inhibitors have been reported (Yaguchi et al (2006) Jour. of the Nat. Cancer Inst. 98(8):545-556; U.S. Pat. No. 7,173,029; U.S. Pat. No. 7,037,915; U.S. Pat. No. 6,608,056; U.S. Pat. No. 6,608,053; U.S. Pat. No. 6,838,457; U.S. Pat. No. 6,770,641; U.S. Pat. No. 6,653,320; U.S. Pat. No. 6,403,588; U.S. Pat. No. 7,750,002; WO 2006/046035; U.S. Pat. No. 7,872,003; WO 2007/042806; WO 2007/042810; WO 2004/017950; US 2004/092561; WO 2004/007491; WO 2004/006916; WO 2003/037886; US 2003/149074; WO 2003/035618; WO 2003/034997; US 2003/158212; EP 1417976; US 2004/053946; JP 2001247477; JP 08175990; JP 08176070).
Certain thienopyrimidine compounds have p110 alpha binding, PI3 kinase inhibitory activity, and inhibit the growth of cancer cells (Wallin et al (2011) Mol. Can. Ther. 10(12):2426-2436; Sutherlin et al (2011) Jour. Med. Chem. 54:7579-7587; US 2008/0207611; U.S. Pat. No. 7,846,929; U.S. Pat. No. 7,781,433; US 2008/0076758; U.S. Pat. No. 7,888,352; US 2008/0269210. GDC-0941 (CAS Reg. No. 957054-30-7, Genentech Inc.), is a selective, orally bioavailable inhibitor of PI3K with promising pharmacokinetic and pharmaceutical properties (Folkes et al (2008) Jour. of Med. Chem. 51(18):5522-5532; U.S. Pat. No. 7,781,433; Belvin et al, American Association for Cancer Research Annual Meeting 2008, 99th: April 15, Abstract 4004; Folkes et al, American Association for Cancer Research Annual Meeting 2008, 99th: April 14, Abstract LB-146; Friedman et al, American Association for Cancer Research Annual Meeting 2008, 99th: April 14, Abstract LB-110) and shows synergistic activity in vitro and in vivo in combination with certain chemotherapeutic agents against solid tumor cell lines (US 2009/0098135).
GDC-0032 (Roche RG7604, CAS Reg. No. 1282512-48-4), named as 2-(4-(2-(1-isopropyl-3-methyl-1H-1,2,4-triazol-5-yl)-5,6-dihydrobenzo[f]imidazo[1,2-d][1,4]oxazepin-9-yl)-1H-pyrazol-1-yl)-2-methylpropanamide, has potent PI3K activity (WO 2011/036280; U.S. Pat. No. 8,242,104; U.S. Pat. No. 8,343,955) and is being studied in patients with locally advanced or metastatic solid tumors.